A new way to generate a broad immune system response against different variants of HIV

9 March 2015

It is estimated that worldwide thirty million people are infected with Human Immunodeficiency Virus (HIV), the virus that causes AIDS. Until now, there is no effective vaccine against HIV. This is a due to the high variability of the virus and to the virus attacking the immune system, thereby hampering efficient immune responses. More research is still needed. Central to the research is the question: how to provoke a massive immune response that can eliminate different variants of the virus? BPRC researchers have tested a possible strategy.

The immune system can eliminate unwanted intruders in many ways. Scientific evidence indicates that protection against HIV is only possible through a concerted action of the different components of the immune system. In addition, the immune response needs to attack virus elements that are present in all HIV variants. It often occurs that vaccination activates a specific branch of the immune system, with the other part of the immune system remaining more or less inactive. A collaboration of several research groups from around the world has now developed a strategy to activate multiple parts of the immune system that should generate a broad immune response. At the BPRC this strategy was tested in monkeys, because monkeys have an immune system that is closely related to that of man.

Previously, using pieces of HIV proteins as vaccine, it had already been shown that good CD4 T-cell and antibody responses could be generated. In the new strategy that was tested at the BPRC this method was combined with an attenuated derivative of the poxvirus that activates a different branch of the immune system. First, rhesus monkeys were injected with the attenuated smallpox virus containing pieces of HIV and at later times with the pieces protein of HIV that are common to the various HIV variants ("conserved peptides"). This strategy indeed induced a broad immune response that was specifically directed against the conserved HIV peptides. Although this was not the case in all animals, this result provides new starting points to develop an effective HIV vaccine. The results of this work have been published in The Journal of General Virology.